The quest has been ongoing for many years

May 7, 2010 10:57 GMT  ·  By

Stem cells may indeed be the first type of cells that develop when a new embryo forms, but the patterns and mechanisms through which they differentiate into the multitude of cell types in the human body needs to be controlled somehow. Researchers believe that “master regulators” are responsible for exerting this type of control, but these mechanisms have thus far eluded detection. Just recently, a group of scientists announced that it may have discovered the master regulators for the self-renewing hematopoietic stem cells (HSC), which the body uses to produce new blood cells.

A large number of science groups, featuring thousands of researchers, are currently at work in identifying the control mechanisms for stem cell differentiation, but the new work is the only one to have produced tangible results thus far. The study was conducted by experts at the Rice University, who collaborated closely with colleagues from the University of Cambridge. Details of their findings appear in the latest online issue of the open-access scientific journal PLoS Computational Biology, a paper of the Public Library of Science.

The researchers determined that a complex of three proteins, called the “Scl-Gata2-Fli1 triad,” is the most likely candidate for designation as the regulatory mechanism behind HSC. “We don't yet have the experimental verification that this is the master-level regulator for HSC, but based on our [computer] model, we can say that it has all the properties that we would expect to find in a master-level regulator,” explains Oleg Igoshin, who is an assistant professor in bioengineering at the Rice University. He also co-developed the new computer simulation, alongside Rice colleague Jatin Narula.

“In examining the results from the model, we found the triad did have the characteristics of a master regulator. The first time it's switched on, all the cells stay on. It also handles deactivation in a controlled manner, so that some cells differentiate and get deactivated and others don't. Finally, it has the ability to discern whether or not the level of signal is present only for a short burst or for a significantly long time,” Narula explains. “It's possible that this triad motif is reused elsewhere. The proteins could be different in each case, but the motif structure of their interconnections is common and may be repeated elsewhere in nature. That's one of the most intriguing aspects of this research,” Igoshin concludes.